Mega Houndoom Pokémon GO will be unlocked in a collaborative challenge for all players during Mega September.
To celebrate the new Mega Raids, Niantic challenged players to complete two million Mega Raids to get Mega Pidgeot last week. This week, the challenge is to complete battles with Mega Pokémon to unlock Mega Houndoom.
Mega Houndoom Pokémon GO: How to Get
From September 11 to September 17, if players collectively complete 275 million battles with Mega Pokémon, Mega Houndoom will be unlocked. Battles that are not GO Battle League battles are eligible for the challenge.
Once Mega Houndoom is unlocked, you can Mega Evolve your Houndoom using Mega Energy. You earn more energy the faster you complete a Mega Raid. Each Mega Evolution uses their own Mega Energy, so if you want to Mega Evolve Houndoom you need to defeat Mega Houndoom in Raids.
The first time you Mega Evolve a Pokémon, it will cost a fair amount of energy. It will be significantly cheaper the second time. Mega Evolution is a temporary state, lasting only for four real world hours. You can only have one Mega Evolved Pokémon at a time.
Make the most out of your Mega Houndoom by completing battles and Raids before its evolution runs out.